Mechanical means were hitherto utilized in the production of the desired profile at the tool or workpiece, for example, when forming such archimedean undercuts with a grinding wheel or disc, at the thread milling cutters or drills. Thus, a cam disc has been used on the circumference of which is provided a grinding curvature which is used to shape the respective workpiece and, by way of a lever system, are therethrough generated the necessary strokes or lifting motions of the workpiece or of the grinding disc.
As a result of attendant mass and vibrational problems of the moving bodies and masses, for example, involving translatory or similar reciprocating movements, the operational speed and the quality are subject to limits set in conformity with the mechanical lever system.
When investigating respective limits of an undercut produced with mechanically controlled operational means it was found, for example, that the upper limit was at about 1500 strokes or lifts per minute. At this upper limit, vibrations of excessive magnitude were experienced, which substantially preclude a higher rate of the strokes or operational movements. Furthermore, retooling for a greater variety of different workpieces becomes cumbersome.